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This is interesting and all, but there is one glaring flaw in all of this at least compared to the human powered plane flight. Looking at all these attempts there is one HUGE part missing. NO CONTROL. THis isn't really flight at all just uncontrolled hovering. I'd like to see this taken to a true flight capable helicopter not just an impractical archaic machine that can't even sustain an actual hover due to built in limitations (mainly the one way drive)

These are the rules for the human powered airplane competition. Note the parts where it says it has to be an actual production worthy craft, but more importantly, capable of sustained flight meeting the airworthiness requirements of fixed wing type aircraft including the controllability around a course. THese can easily be adapted to rotorcraft in a sustained hover controlled by the pilot and not by ground crew holding on to the machine. THese attempts have proven that a human powered rotorcraft is capable of flight I'd just like to see it expanded to cover the same parameters actual helicopters have to meet. As for designs, there are plenty of helicopter designs already and adapting a human power train might not be as hard as people think.

This is interesting and all, but there is one glaring flaw in all of this at least compared to the human powered plane flight. Looking at all these attempts there is one HUGE part missing. NO CONTROL. THis isn't really flight at all just uncontrolled hovering. I'd like to see this taken to a true flight capable helicopter not just an impractical archaic machine that can't even sustain an actual hover due to built in limitations (mainly the one way drive)

Control is kind of pointless without flight/lift. Comparing fixed-wing flight and helicopter flight requirements, especially in terms of human power is apples and oranges. Fixed wings have the distinct adavantage of lift being provided by wing surfaces so the human power component can be commensurately less. If the helicopter attempts for the Sikorsky seem impractical or archaic, then apparently some of the attempts at fixed wing flights have been lost in the mists of time. I expect that by today's standards they would also seem impractical and archaic.

These are the rules for the human powered airplane competition. Note the parts where it says it has to be an actual production worthy craft, but more importantly, capable of sustained flight meeting the airworthiness requirements of fixed wing type aircraft including the controllability around a course. THese can easily be adapted to rotorcraft in a sustained hover controlled by the pilot and not by ground crew holding on to the machine. THese attempts have proven that a human powered rotorcraft is capable of flight I'd just like to see it expanded to cover the same parameters actual helicopters have to meet.

Adjusting the requirements for one type of flight to another doesn't impact the challanges of meeting those requirements any easier to obtain.

The Sikorsky Challange exists for one simple reason: "There are feelings among some people that only a radical departure from conventional helicopter configurations will yields the prize."

While whatever takes the challange may not be practical for production, the materials and designs will certainly be worth incorporating into future production helicopters.

A helicopter that can be powered by a human would have to be a design (at least from a lift ability viewpoint) that would have to be exceedingly frugal and would lead to helicopters with lower fuel requirements that currently existing designs.

Sometimes, I think, a fresh perspective is needed. Otherwise, we just keep doing the same old thing, only 10% better.

interesting perspective Tom. Which begs the question of why they copied the Tip Votex for the basis of their design making what seem like minor structural improvement changes.

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Citations and/or references are always appreciated.

ATB,Sam

I can only give examples of some unconventional current designs that scaled right might be workable. First one that comes to mind is the ch-47 chinook. Not for its size but the highly efficient twin counter rotating blades that cancel out the torque effect on the fuselage. THe second more conventional one is Sikorsky's own "sky crane" that has a unique blade design that actually creates up to 5 times the lift or more(can't find exact numbers atm) per engine hp input. THe Kamov KA-50 Hokum twin "stacked rotor" design for another take on atacking the torque issue. Though not a helicopter per say but more of a hybrid would be the auto gyro built for the james bond movies and yes it is a real aircraft. All these have features that could prove useful. Even the overall design of some may be adaptable. Heck even Davinci's screw type bladed rotor craft has been proven plausible.

Now as far as the comparison to fixed wing aircraft, its not that far off. THe main difference is that on a helicopter you are rotating the wing to create the flow over the aerofoil to generate the lift but the same design principal that go into the profile of a fixed wing goes into rotor blade profile design. IF you look close at the tip vortex and UMD's designs they are both using established fixed wing profile designs in the rotor blades at a fixed pitch just like an airplane prop. This makes it necessary to have more power applied to get more lift, quickly reaching beyond human strength. Helicopters use variable pitch systems to overcome this limitation needing only enough power to spin the rotor at the desired rpm. The problem i see here is simplifying the current squash plate design into something less cumbersome. Will take a lot more research to come up with something.

All this aside though, making the challenge to require a sustained hover (using their current parameters) controlled in height and position by the pilot only would IMO bring it more in line with real world aircraft needs and to step from there into full controlled heli flight seems more plausible. Nothing in either of these two machines can be taken into real world craft other than the already established principals, and thats where I have a problem with the designs though I may be alone in that ideal.

Your early fixed wing examples Sam don't really apply in the same manner as there were aspect of all those designs taken and applied to later designs. Personally I wouldn't want to be in a craft that you can't control the direction of flight or had such a limited flight sustainability "engineered" in.

It is definitely a challenge meant to get people thinking outside the box, with current helicopter designs the sustainable power output of a human just isn't enough to provide sustained flight. I think you need to go back to the simple genius of the first successful powered heavier then air flight achieved by the Wright Brothers.

The statement has also been made that without control it isn't flight. Do they need control at this point? The rules allow an external crew of 2 people to help guide and stabilize the craft and most importantly require the machine to hover in place staying within a 10 meter square. This challenge isn't meant to promote controllable flight as properly defined for a fixed wing aircraft, for this challenge the definition of flight is just to get off the ground for 1 minute while staying in one place, and to achieve a minimum hieght of 10 meters at some point during the flight. So 3 axis control isn't a neccesity, but is it still needed? Probably, at least 2 axis, pitch & roll, I think we can ignore yaw as long as the craft doesn't spin out of control like a single rotor helicopter will without yaw control.

The genius of the Wright Brothers that finally achieved our first powered flight was based on a few revolutionary idea's, the most important in their eyes was control. But then they would be moving through the air at speed and had seen the outcome of earlier experiments where control was lacking, that being failure and usually death.

Another of the Wright's revolutionary idea's and the most pertainant to this discussion was the realization that a propeller is simply a rotating wing. Earlier experimenters had used basically flat paddles and all had failed to achieve the neccesary thrust.

This is where I'm seeing all these challengers fall short on their designs too, they have the rotating wing thing down of course, but they are stuck in the flat paddle mode of thought otherwise. As the Wrights also realized a propeller blade needs a different airfoil design throughout it's length, it's airspeed changes dramatically from the center of rotation to the tips furthest from the center. They could not generate the thrust needed with the engine technology of the time from a constant airfoil propeller. Only by designing their propeller with the most efficient airfoil shape at each point along it's length for the airspeed it would be operating in did they succeed.

For this challenge I would also look again at another of the Wrights idea's as used in their wings to vary the lift for control, "Wing Warping". The Wrights twisted their wings for control rather then having mechanical flaps, twisting the rotating wings rather then rotating the whole wing would be far simpler mechanically and more efficient since we need varying lift and drag along the length anyway ( I know I'd have to draw a picture to get this idea across but it works I tell you, and is stupid simple mechanically, probably why these "edjookated" engineer types haven't thought of it, but then the Wright's proved 100 years ago that you actually need a couple of uneducated "Hammer and bailing wire" bicycle mechanics to achieve flight)

Since the rules do allow using the energy stored in the rotating blades and only require achieving a 3 meter height momentarily another solution is written right into the challenge. Get the craft off the ground and hover for the first minute, I like the ground effects mode as being highly effecient then twist the blades for more lift and use the stored energy to jump up to the 3 meter height. Of course make sure no structure is pointed at the pilots 'arse' when it descends once that stored energy is depleted

And guess what? since I like the quad rotor ground effects design for this challenge I just added pitch & roll control along with forward & backward, and side to side movement by simply by varying the lift of each rotor independently. Personally I would use a basic processor hooked to some pitch and acceleration sensors and running some servo's for blade control to take the level/static hovering job off the pilot, it's easy then to add pilot input into the system for directional control once flight is achieved. I still need yaw control but that's also simple to add when the time comes.

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And guess what? since I like the quad rotor ground effects design for this challenge I just added pitch & roll control along with forward & backward, and side to side movement by simply by varying the lift of each rotor independently. Personally I would use a basic processor hooked to some pitch and acceleration sensors and running some servo's for blade control to take the level/static hovering job off the pilot, it's easy then to add pilot input into the system for directional control once flight is achieved. I still need yaw control but that's also simple to add when the time comes.

The words simply and easy don't come into play with this challenge. You're a caricature of an arm chair quarterback.

And guess what? since I like the quad rotor ground effects design for this challenge I just added pitch & roll control along with forward & backward, and side to side movement by simply by varying the lift of each rotor independently. Personally I would use a basic processor hooked to some pitch and acceleration sensors and running some servo's for blade control to take the level/static hovering job off the pilot, it's easy then to add pilot input into the system for directional control once flight is achieved. I still need yaw control but that's also simple to add when the time comes.

The words simply and easy don't come into play with this challenge. You're a caricature of an arm chair quarterback.

Ah yes but sometime the simple ideas are the ones that work and work well John

@ MikeYou said it a bit better than I did and your ideas of twisting the rotors creating a 2 axis control is sound and is already in use today. The CH-47 Chinook uses just that type of 2 axis control. The rotors tilt front/rear and right/left to control direction in flight and stability in a hover. The wing warping idea though it works on fixed wing would be a mechanical nightmare to implement on a rotating wing. One of Igor Sikorsky's early concept designs tried and failed at this leading to the current squash plate solution to rotor pitch control.

On the design they are using, a couple of changes I would try is changing the 1-way drive to a perpetual loop drive. A servo mechanism such as that use on the Osprey VTOL to tilt the entire rotor system would add the directional stability in small adjustments. Al thats left is to design an efficient prop blade profile which you can go to the RC industry and scale up a few of the rotor blade designs used on rc heli's . A spinning wing (prop) as the Wright brothers proved needs to create more lift as you get closer to the center of rotation where the speed of the blade is slower than out at the tip. With the fixed profile along the length of the blade that they used the lift generated moves out toward the tips as rotor speed increases.

And guess what? since I like the quad rotor ground effects design for this challenge I just added pitch & roll control along with forward & backward, and side to side movement by simply by varying the lift of each rotor independently. Personally I would use a basic processor hooked to some pitch and acceleration sensors and running some servo's for blade control to take the level/static hovering job off the pilot, it's easy then to add pilot input into the system for directional control once flight is achieved. I still need yaw control but that's also simple to add when the time comes.

The words simply and easy don't come into play with this challenge. You're a caricature of an arm chair quarterback.

Maybe I'm crazy, but it seems like nature has figured this out already. I eeked through Physics in college enough to realize not only that those guys are pretty sharp, but also that they rely heavily on classical thought.

Watching a bumble bee and other winged insects, they seem to vibrate their wings to create lift. Birds are fast agile creatures whose wings can generate lift whether they are are flapping or gliding - little bodies tuned to generate enough speed to fly. The last thing that they resemble is a machine, they seem pretty kite-like actually.

Maybe Ca Ike is right - if you want that 1/4 million, you gotta get WAY outside the box.

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